[pilif]

And then you end up with people complaining about bloat because the browser contains code for every possible state of all these settings.

[snaky]

It's clearly not the case when the checkbox you adding is an option to turn off some feature enabled by default.

No, not the feature all other components do need so much you have to work around by adding another zillion lines of code in other places of your program to deal with the case it turned off.